But manager Brendan Rodgers has tried to smooth the situation with Johnson, who was signed for £17.5 million from Portsmouth in 2009, by making it clear that he would like to keep the defender.

"We want to keep Glen here," Rodgers told the Liverpool Echo. "There is no question about that, especially now he's in this form. He's 29 and we feel that he has still got good years ahead of him.

"No contracts will be looked at until the summer but his will be a priority for us, especially if he continues in the form that he's in."

An obstacle to a new agreement could by Johnson's wage expectations with the defender likely to have to take a cut in his reported £110,000-a-week salary in order.

Fenway Sports Group, Liverpool's Boston-based owners, have previously been unwilling to increase the salaries of players once they reach 30. Johnson will celebrate his 30th birthday in August, and his age may also be a factor in negotiations.

Asked if Johnson's age and salary would be an issue when it came to discussing a new deal, Rodgers said: "It just means you just have to sit, debate and discuss what's best for the club and the player.

"The beauty of this is we want to keep Glen and Glen loves it here. We just need to find a solution which is good for both.

"If we can do that, then the club will have a very good player for years to come.

"We have other players such as young Jon Flanagan who only has one year left, while Jordan Henderson only has two years left. They have been great and we want to look at those contracts.

"That's something that will be for the summer. The players can do themselves no harm by continuing to play in the form they are in. The club will then take a close look at it."

Johnson has struggled with injuries this season - he did not play for seven weeks after spraining his ankle in early September, then had another month on the sidelines from mid-January because of groin and ankle problems.

But Rodgers felt that the defender's performance as Liverpool won 6-3 at Cardiff on Saturday demonstrated that he is regaining his best form.

The manager said: "Now he's feeling fresh and playing for the first time in ages without any injuries. Now you see that mobility and running power that he has. I thought Glen was outstanding against Cardiff.

"It's important for me, with how we play, that the full-backs can get up, join in and make runs in behind. We are seeing now the player we all know Liverpool had - which is one of the best full-backs in the world."